It is previously known to solidify a spent ion exchange resin in cement or bitumen. However, by such a measure the volume is heavily increased. Furthermore, in the case of solidification in cement, the stability against leaching is not very good. In the case of solidification in bitumen the fire hazards thereof is a problem.
Moreover, it is previously known, for instance from Swedish patent specification No. 8101801-2, that the volume of a spent ion exchange resin can be reduced by an incineration thereof. According to said Swedish patent specification the incineration residue is then heated to sintering or melting, a stable product being obtained thereby. The measure of cementing the incineration residue has been considered improper due to the bad stability against leaching which has been observed when solidifying a non-incinerated ion exchange resin in cement.